1. Field of the Invention
This invention relates to an acoustical barrier, and more specifically to an acoustical barrier having a flexible seal through which connectors, modules and the like can pass.
2. Description of the Related Art
Articles, such as steering columns, blower attachments, brackets, electrical and mechanical cables, are commonly passed through an aperture in barrier walls of vehicles and other structures. It is desirable to block the transfer of sound through the wall from the engine compartment into the passenger compartment. A moisture seal is disposed in the opening between the wall and the cable or column to prevent moisture from passing from one side of the wall to another. Typically, a foam insulation layer and a mass layer have been mounted to the wall. Openings in the mass layer for the cable or articles mounted to the wall have been defined by a support rib which extends from an edge of the mass layer opening to the wall.
The acoustical barrier must be capable of adapting to tubes, wires and components of different diameters and cross-sectional shapes. Preferably, the acoustical barrier conforms exactly to the shape of the tube, wire or component. An acoustical barrier for an automobile HVAC unit has previously been formed in an aperture for tubing in an acoustical panel by forming in the panel radially extending, triangular sectors defined by radial slits originating from a large central aperture to radially spaced apertures. The sectors can generally conform to the shape of a tube or cable passing through the aperture defined by the ends of the radially extending sectors by the deflection of the sectors. See U.S. Pat. No. 5,243,153 to Holwerda, issued Sep. 7, 1993. Other seals for tubing in other environments are disclosed in U.S. Pat. Nos. 3,365,761 to Kalvig, issued Jan. 30, 1968; and 3,162,412 to McEntire, issued Dec. 22, 1964. The radial sectors of these references help to conform the aperture to the size of the tube or wire. However, the radially extending slots and the originating apertures provide for the uninhibited transfer of sound from one side of the acoustical barrier to the other and retard the effectiveness of the acoustical barrier.
U.S. Pat. No. 3,881,752 to Fujishima, issued May 6, 1975, discloses a generally circular resilient plastic sheet having an undersized central aperture that is slidably mounted onto a pipe so that the strain resulting from the stretching of the aperture elongates the sheet around the pipe into a cone-shape. The plastic sheet is moved along the pipe so that the end of the plastic sheet abuts the wall through which the pipe passes. The tightly drawn plastic sheet can act as a diaphragm to transmit noise passing through the aperture in the wall, thereby retarding the acoustic sealing properties of the plastic sheet.
Although the previous devices all attempted to provide an acoustical barrier for tubes or cable passing through an aperture in a wall, all of the previous acoustical barriers have one or more undesirable characteristics. Further, all of the previous acoustical barriers failed to suitably perform both as an acoustical barrier.